After Jack had related the tale of the horseshoe and its relation to their present situation, Arnold suggested that they visit Frank's camp and then go aboard the Fortuna. This met the approval of all the boys. A trip to the wreckage disclosed the fact that Frank had made his bed on the hard, smooth sand with a fire in front of him for protection from the chill winds of the night.
"Here's the fire stick," exultantly cried Arnold. "Gee, won't I have a great story written about this adventure when I get back to little old Chi. Sherman Street won't know me when I arrive."
"Hurray," cried Harry who had wandered a short distance from the others. "Hurray, I've found the horse that belongs to the horseshoe! Here he is buried upside down in the sand."
Hastening to the spot indicated the boys saw what looked to be a horse's foot upside down in the sand. So startling was the resemblance that Jack and Arnold were completely deceived for a moment, but Frank's laugh soon indicated that they had been mistaken.
"What is it?" asked Arnold eagerly. "Gee, but I see so many new things here I don't know which to write a story about first."
"Better not write any story about this," admonished Frank. "The wonderful phenomenon you see before you, my friend, is not a horse at all. It is merely a crab shell from which the crab has gone."
"A crab shell?" repeated Arnold in wonderment. "A real crab?"
"Sure enough," declared Frank. "The underside of the shell has exactly the same outlines as the under side of a horse's foot. This fellow has projecting from the heel a spikey tail that is hard and sharp at the end. The whole thing, as you see, is dried and hardened by exposure to the weather. The crab has been gone a long time."
"I'm going to take it along," asserted Arnold. "I'll put it in my locker and make a collection of things I pick up. I'd like to see a flounder now so as to recognize one the next time I see it."
"I have a fine big fellow at the place I had my fires," Frank answered. "We'll go over there and see how he's getting on. I got him last night. I think he must weigh as much as three or four pounds."